Influence of Carbon Black Contents and Rubber Compositions on Formation of Wear Debris of Rubber Vulcanizates

Wear particles of the model tread compounds for bus and truck tires were made using a laboratory abrasion tester and characterized based on their size distributions, shapes, and crosslink densities. The influence of the carbon black contents and rubber compositions (NR= 100 and NR/BR= 80/20) on the production of wear particles was investigated. The wear particles were separated according to size using a sieve shaker. The shape properties of the wear particles were analyzed using an image analyzer and scanning electron microscopy (SEM). Their shapes were observed as tiny stick cookies or sausages with bumpy surfaces. The particle size distribution tended to be smaller with increasing carbon black content. Moreover, the particle size distributions of the NR = 100 samples were larger than that of the NR/BR blend samples. There were different filaments in the wear particles. The filament diameters tended to be thinner with increasing carbon black content. The crosslink density increased with increasing carbon black content, and the crosslink densities of the NR= 100 samples were lower than those of the NR/BR blend ones. The particle size distribution tended to be smaller with increasing crosslink density. Based on the experimental results, the wear particles can be produced by detaching debris from the main body through repetitive strain and recovery.